1. Field of the Invention
The invention relates to symbol generators particularly with regard to digital to stroke generators. More specifically, the invention relates a digital stroke generator having the capacity to dynamically rotate a symbol placing only a minimal computation burden on the host processor.
2. Description of the Prior Art
Prior art stroke generators typically have a fixed character memory with fixed .DELTA.x and .DELTA.y steps that define the strokes that make up a character to be displayed. As an example of a prior art stroke generator, reference is made to U.S. Pat. No. 4,115,863 entitled "Digital Stroke Display with Vector, Circle and Character Generation Capability", issued to Richard R. Brown on Sept. 19, 1978 and assigned to the assignee of the present invention. The use of fixed character memory is often undesirable in that it prevents any dynamic rotation of the character set. A minor improvement can be had by replacing the fixed character memory with a programmable memory (RAM). This approach enables the rotation of characters through direct manipulation of the .DELTA.x and .DELTA.y steps which make up the character as generated by the host processor. The host processor must compute the rotated stroke angle and the correesponding .DELTA.x and .DELTA.y steps. For displays that contain many different rotating characters, the computation burden of rotating many characters may be prohibitive.